CN114483056B - Method for treating collapse roof caving hole of high-speed railway shallow-buried tunnel within 15m of height of collapse cavity - Google Patents
Method for treating collapse roof caving hole of high-speed railway shallow-buried tunnel within 15m of height of collapse cavity Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 79
- 239000010959 steel Substances 0.000 claims abstract description 79
- 239000004567 concrete Substances 0.000 claims abstract description 61
- 238000010276 construction Methods 0.000 claims abstract description 58
- 239000002689 soil Substances 0.000 claims abstract description 43
- 239000002893 slag Substances 0.000 claims abstract description 40
- 238000005507 spraying Methods 0.000 claims abstract description 30
- 238000009412 basement excavation Methods 0.000 claims abstract description 22
- 238000007789 sealing Methods 0.000 claims abstract description 19
- 238000003672 processing method Methods 0.000 claims abstract description 5
- 230000003014 reinforcing effect Effects 0.000 claims description 22
- 239000011435 rock Substances 0.000 claims description 21
- 238000005422 blasting Methods 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 11
- 238000003466 welding Methods 0.000 claims description 10
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 7
- 239000004570 mortar (masonry) Substances 0.000 claims description 5
- 239000002352 surface water Substances 0.000 claims description 5
- 238000005336 cracking Methods 0.000 claims description 3
- 230000002093 peripheral effect Effects 0.000 claims description 3
- 239000002023 wood Substances 0.000 claims description 3
- 238000005553 drilling Methods 0.000 claims description 2
- 239000011378 shotcrete Substances 0.000 abstract description 5
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- 238000010586 diagram Methods 0.000 description 2
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/01—Methods or apparatus for enlarging or restoring the cross-section of tunnels, e.g. by restoring the floor to its original level
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/003—Linings or provisions thereon, specially adapted for traffic tunnels, e.g. with built-in cleaning devices
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/107—Reinforcing elements therefor; Holders for the reinforcing elements
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F16/00—Drainage
- E21F16/02—Drainage of tunnels
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Abstract
The invention provides a collapse roof caving in-tunnel processing method for a high-speed railway shallow-buried tunnel within 15m of height of a collapsed cavity, belonging to the technical field of underground engineering and comprising the following steps of S1, clearing soil in the collapsed cavity; s2, replacing and filling the slag in the hole, and replacing and filling hole slag with higher overall strength; s3, constructing a collapse treatment operation platform, and raising the height of the steps according to a three-step excavation method; s4, performing collapsed cavity supporting treatment, performing concrete spraying construction, and supporting the inner wall of the collapsed cavity; s5, top arch sealing treatment, namely, carrying out upper step inner sealing treatment on the collapse cavity by adopting a steel arch frame, a net and sprayed concrete; s6, performing full-closed treatment, excavating middle steps and lower steps, sealing full-circle steel arch frames, hanging nets and spraying concrete; s7, constructing inverted arch concrete; s8, constructing second lining concrete; s9, carrying out hole top collapsed cavity backfilling construction, and carrying out layered backfilling and tamping. The invention has low construction cost and high speed.
Description
Technical Field
The invention belongs to the technical field of underground engineering, and relates to a method for treating collapse roof caving holes of a high-speed railway shallow-buried tunnel within 15m of the height of a collapse cavity.
Background
In shallow tunnel excavation construction, due to various reasons, collapse and even roof fall often occur. Collapse and roof fall refer to the phenomenon that the tunnel (or tunnel) always collapses upwards after collapse and is directly connected with the surface of the ground. For a shallow tunnel, the thickness of rock soil covering the top of the tunnel is generally thinner and is not more than 35 m, so that for the shallow tunnel, a shaft treatment method is mainly adopted, firstly, a net anchor is sprayed and supported from top to bottom to reinforce a collapsed cavity, after rock soil on the inner wall of the cavity is stabilized, a steel arch frame at the top of the tunnel, a reinforcing net is hung, a concrete is sprayed and supported to seal a top arch, and finally, the collapsed cavity is backfilled from bottom to top. For collapse roof fall within 20m, an open cut treatment method can be adopted to firstly carry out slope excavation on a collapse cavity from the ground surface to form a stable side slope with the ratio of 1:1, then carry out anchor net spraying, supporting and reinforcing on the side slope, then carry out steel arch centering on the top of the tunnel, hang a reinforcing mesh and spray concrete to support and seal a top arch, and finally carry out collapse cavity backfill from bottom to top. But all require a certain construction site within a certain range of the ground surface collapse cavity. No reference scheme exists at present when the collapse roof fall treatment work is started rapidly under the condition that the ground surface at the top of the collapse cavity does not have a construction site.
Disclosure of Invention
The invention aims to provide a method for treating collapse roof caving holes of a high-speed railway shallow-buried tunnel within 15m of the height of a collapse cavity. The invention solves the problems in the background technology, completes the rapid construction and reduces the construction cost.
In order to solve the technical problems, the invention adopts the technical scheme that: by researching and optimizing collapse treatment procedures and excavating support technology, the method for treating the collapse roof fall tunnel of the high-speed rail shallow tunnel within 15m of the height of the collapse cavity is reasonably determined. The method specifically comprises the following steps of,
s1, firstly, collapse treatment construction is started in the cave, firstly, slag in the cave is cleaned, soil in the collapse cavity is removed, and the slag of the collapse body is conveyed to the outside of the cave to be discarded to a slag dump until the collapse cavity and the slag in the cave are completely removed and the collapse cavity is exposed;
s2, replacing and filling the slag in the hole, conveying all the collapsed slag in the hole out of the hole, and replacing and filling hole slag with high overall strength;
s3, building a collapse treatment operation platform, namely building the collapse treatment operation platform by adopting the hole slag materials changed and filled in the step S2, wherein the height of the platform is the height of the upper step according to a three-step excavation method;
s4, carrying out collapsed cavity supporting treatment, carrying out concrete spraying construction on the surface of the inner wall of the collapsed cavity on the constructed collapse treatment operation platform, and supporting the inner wall of the collapsed cavity;
S5, top arch sealing treatment, namely, carrying out upper step inner sealing treatment on the collapse cavity by adopting a steel arch frame, a net and sprayed concrete;
s6, performing full-closed treatment, excavating middle steps and lower steps, and performing full-circular closed steel arch frames, net hanging and concrete spraying;
s7, constructing inverted arch concrete;
s8, constructing secondary lining concrete of the full section according to the design requirement;
and S9, performing cavity collapse backfill construction on the top of the tunnel, performing cavity collapse backfill work in the later land expropriation of the ground surface, backfilling natural soil according to design requirements, and naturally settling to be compact.
Further, before step S1, earth surface seepage control is performed, a rain shed is built on the earth surface, and drainage ditches are manually dug around the collapsed cavity to prevent surface water from flowing into and permeating into the collapsed cavity in a large amount.
Furthermore, a rain shed is erected in the range of 10.0 m from the edge of the landslide cavity on the ground surface, a temporary drainage ditch is excavated about 9.0 m away from the edge, the width of the ditch is 50 cm, the depth of the ditch is 30 cm, mortar is smeared, and the drainage ditch extends out of the landslide influence range so as to prevent the landslide cavity from being influenced by seepage of rainwater on the ground surface.
Further, the step S5 includes the following steps:
1) erecting top arch steel arch frames, namely welding the steel arch frames at the top arch part into a whole by every 3 steel arch frames according to a designed interval, welding an inner double-layer reinforcing mesh and an outer double-layer reinforcing mesh, erecting each group of steel arch frames at the top arch part, and manually assisting to adjust the direction and the angle of the steel arch frames under the protection of surrounding rocks at arch corners at two sides;
2) Spraying concrete on the top arch;
3) and (3) constructing a locking guide pipe, arranging a small locking guide pipe with phi 42mm and L =4.0 m for each steel arch frame according to the design requirement of collapse treatment, adding a reinforcing guide pipe contraction foot with phi 108 mm and L =5.0 m between every two steel arch frames, and grouting in the guide pipe.
Furthermore, welding I22 steel arches at each 3-arch part at the designed interval of 0.6 m outside the tunnel into a whole by adopting I18I-steel, welding an inner layer reinforcing mesh and an outer layer reinforcing mesh by adopting a phi 8 mm reinforcing steel bar, wherein the mesh size is 20cm multiplied by 20cm, and the inner layer reinforcing mesh is 1.2 m 3 Erecting each group of steel arch frames to a top arch part by a front arm of the back shovel, and assisting to adjust the direction and the angle of the steel arch frames under the protection of surrounding rocks at arch angles at two sides by manpower; the arch springing is made of I18I-shaped steel, concrete cushion blocks, wood wedges and other materials, and 6 steel arch frames are erected in two times;
adopting an Anhui Jiale HSC-3015C type wet spraying trolley, and spraying concrete on a top arch to reach the thickness of 30 cm;
according to the design requirement of collapse treatment, 12 small guide pipes with locking feet are arranged on each steel arch, 6 guide pipes on each side are made of phi 42mm seamless steel pipes, the length of each guide pipe is 4.0m, except for the small guide pipes with the reduced feet required by the design, 2 reduced feet of reinforcing guide pipes are additionally arranged between every two steel arches, 1 guide pipe on each side is made of phi 108 mm seamless steel pipes, the length of each guide pipe is 5.0 m, and grouting is conducted in the guide pipes.
Further, in step S6, the top arch closing construction is finished, the lower step and the inverted arch are excavated, I22 steel arch frames are adopted for full-circle closing, and the steel mesh is hung and concrete is sprayed.
Further, the inverted arch concrete construction adopts 36 m long hydraulic inverted arch trestle construction; the full-section secondary lining concrete adopts a two-lining steel mould trolley, and an HBT60A-1406 type concrete pump pumps concrete to be put into a warehouse.
Further, in step S9, backfilling natural soil, naturally settling to be dense, ensuring that the backfilled soil is slightly higher than the elevation of the peripheral earth surface after the backfilling is finished, filling planting soil with a thickness of not less than 1.2 m on the earth surface, in the backfilling process, directly pouring soil materials vertically, repairing a slope in temporary land acquisition, and pushing the slope by using a loader to prevent the soil body from dumping to cause cracking of the second lining concrete in the hole.
Further, after the backfilling is finished, the subsequent construction is carried out according to the following steps,
1) controlling the single-cycle footage to be 0.6 m;
2) supporting the pipe shed in construction;
3) in the top arch rock ultrathin tunnel section, 3 obliquely upward 45-degree exploration holes are drilled by hand wind at each excavation blasting circulation, the aperture phi is 42mm, the length is 5.0 m, the thickness of a rock stratum above an arch part is explored, and blasting parameters are determined.
Further, after the collapse cavity is processed, the method is as follows 
Adopting a three-step core soil excavation method for the level surrounding rock;
during construction, excavating a pipe shed forwards within 25 m, digging one row of pipe sheds within 140 degrees in the circumferential direction of an arch part of each 12.5 m, wherein the circumferential distance is 30 cm, the pipe sheds are made of seamless steel pipes with the diameter of 89 mm, the length of each pipe shed is 15.0 m, and the lap joint length between two rows is 2.5 m;
and 3 obliquely upward 45-degree exploration holes with the length of 5.0 m are drilled every time blasting circulation is excavated.
Compared with the prior art, the invention has the advantages and positive effects as follows:
1. the invention is used for the collapse roof fall of a shallow tunnel with the buried depth within 15 m, firstly, the collapse treatment construction is started in a hole under the condition that the ground surface does not have a collapse cavity treatment construction site, firstly, the slag in the hole is cleaned, the slag is changed and filled, an operation platform is built, then, concrete is sprayed from the hole to an upper collapse cavity for supporting, finally, the construction method of steel arch frames, net hanging and concrete spraying closed top arches is carried out from the hole, then, the hole internal support of full-ring steel arch frames in the hole is carried out, the reinforced concrete is secondarily lined, and finally, the collapse cavity is backfilled from bottom to top.
2. In the process of arch crown sealing treatment, the strength and stability of arch crown sealing are ensured according to certain steps, steel arch frames are welded and connected into a whole outside a hole according to a designed interval, an inner layer reinforcing mesh and an outer layer reinforcing mesh are welded, and concrete is sprayed on the arch crown; meanwhile, a reinforced locking pin guide pipe is arranged, grouting is conducted in the guide pipe, and closed efficiency and stability are improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic view of a collapsed geological section according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a round pothole with a diameter of about 10.5 m formed after collapse according to an embodiment of the invention;
FIG. 3 is a schematic diagram of the structure of the collapse roof fall process of the present invention.
Reference numerals:
1-a ground line; 2-a collapsed cavity; 3-rock-soil boundary line; 4-collapsing slag soil; 5-step up; 6-lower step; 7-tunnel.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.
The following detailed description of specific embodiments of the invention refers to the accompanying drawings.
As shown in fig. 1-3, the method for treating the collapse roof fall hole of the high-speed railway shallow-buried tunnel within 15m of the height of the collapsed cavity comprises the following steps:
s1, firstly, collapse treatment construction is started in the cave, firstly, slag in the cave is cleaned, soil in the collapse cavity is removed, and the slag of the collapse body is conveyed to the outside of the cave to be discarded to a slag dump until the collapse cavity and the slag in the cave are completely removed and the collapse cavity is exposed;
s2, replacing and filling the slag in the hole, conveying all the collapsed slag in the hole out of the hole, and replacing and filling hole slag with high overall strength;
s3, building a collapse treatment operation platform, namely building the collapse treatment operation platform by adopting the hole slag materials changed and filled in the step S2, wherein the height of the platform is the height of the upper step according to a three-step excavation method;
S4, carrying out collapsed cavity supporting treatment, carrying out concrete spraying construction on the surface of the inner wall of the collapsed cavity on the constructed collapse treatment operation platform, and supporting the inner wall of the collapsed cavity;
s5, top arch sealing treatment, namely, carrying out upper step inner sealing treatment on the collapse cavity by adopting a steel arch frame, a net and sprayed concrete;
s6, performing full-closed treatment, excavating middle steps and lower steps, and performing full-circular closed steel arch frames, net hanging and concrete spraying;
s7, constructing inverted arch concrete;
s8, constructing secondary lining concrete of the full section according to the design requirement;
and S9, performing cavity collapse backfill construction on the top of the tunnel, performing cavity collapse backfill work in the later land expropriation of the ground surface, backfilling natural soil according to design requirements, and naturally settling to be compact.
Further, before step S1, earth surface seepage control is performed, a rain shed is built on the earth surface, and drainage ditches are manually dug around the collapsed cavity to prevent surface water from flowing into and permeating into the collapsed cavity in a large amount.
Further, step S5 includes the following steps of 1) erecting top arch steel arch frames, welding the steel arch frames at the top arch part into a whole outside the tunnel according to a set of every 3 trusses at a designed interval, welding the inner and outer double-layer reinforcing meshes, erecting each set of steel arch frame at the top arch part, and manually assisting in adjusting the direction and angle of the steel arch frame under the protection of surrounding rocks at the arch corners at two sides; 2) ejecting concrete; 3) and (4) constructing a foot locking guide pipe, arranging a small foot locking guide pipe for each steel arch frame according to the design requirement of collapse treatment, additionally adding a reinforced guide pipe foot between every two steel arch frames, and grouting in the guide pipe.
Further, after the backfilling is finished, the subsequent construction is carried out according to the following steps:
1) controlling the single-circulation footage, finishing the treatment of the collapse cavity, and adopting a three-step core soil excavation method according to the grade surrounding rock, wherein the single-circulation footage is controlled to be 0.6 m;
2) supporting the pipe shed in construction;
3) in the top arch rock ultrathin tunnel section, 3 obliquely upward 45-degree exploration holes are drilled by hand wind at each excavation blasting circulation, the aperture phi is 42mm, the length is 5.0 m, the thickness of a rock stratum above an arch part is explored, and blasting parameters are determined.
Example (b): in collapse roof caving treatment construction of the flexible mountain tunnel from the Weifang to the smoke bench, the thickness of the covering layer above the tunnel roof is 15.27m, the ground surface around the collapsed cavity at the top of the tunnel is not in a land acquisition range, and the collapsed cavity can be treated only by land acquisition again, which needs a long time.
20 days and nights at 20:04 of 9 months and 20 days in 2021, the tunnel face (DK 95+ 403.02) on the working face at the entrance of the tunnel is detonated, the single-cycle footage is 3.0 m, and the mileage of the primary support steel arch is DK95+ 402.49. After blasting and smoke discharging, blasting at the rate of 20:30 and safety treatment personnel enter the tunnel, planning to carry out safety prying operation, finding that the vault of the tunnel has the phenomena of falling rocks and falling blocks, immediately pulling up a warning line, informing construction operators and equipment to immediately evacuate from the site, and simultaneously arranging personnel to carry out on-duty observation. 7:23 in the 21 st morning, the top arch has large collapse, the collapsed body enters the hole and mainly comprises yellow saturated soil bodies, and a small amount of weathered rock is sandwiched between the yellow saturated soil bodies; the natural slope ratio of the collapse body in the hole is about 1:1.5, and the collapse geological section is shown in figure 1. Through the site observation of Wei cigarette high-speed railway company, design, supervision and construction unit, the completed in-hole support is preliminarily confirmed to be basically stable without obvious deformation; designing and excavating height 121.064 m of a top arch of a collapse section, and actually measuring the buried depth of the tunnel top by 15.27 m; the ground surface at the top of the cave is an apple orchard and a ginger field, and a round pot hole with the diameter of about 10.5 m is formed after collapse, as shown in figure 2; the range of the mileage of the surface cavity is DK95+ 401.321-DK 95+411.821, the inner wall of the collapsed cavity is steep, and the soil body is basically stable.
1. Difficulty of landslide treatment
1) The ground surface construction site problem. The ground surface of the tunnel top has no collapse treatment construction site, and collapsed cavities cannot be treated from top to bottom by adopting a shaft treatment method or an open cut treatment method conventionally.
2) The seepage prevention of surface water. Although the collapse period is at the end of the 9 th late ten days of the rainy season, sporadic drizzle exists, and the collapse period is influenced by the fact that the drizzle penetrates into the collapse cavity to be stable.
3) And the stability in the collapsed cavity is solved. The collapsed cavity is higher, the covering layer is mainly soil, and the problem of inner wall soil collapse exists.
4) The soil body collapse in the hole. The collapsed soil in the hole is in a saturated state, has low bearing capacity and is not suitable for building a collapse treatment operation platform.
2. Processing scheme formulation
For collapse roof fall within 35 m of the collapsed cavity, firstly performing anchor net spraying support on the inner wall of the collapsed cavity from top to bottom by adopting a shaft treatment method, then performing support and lining from the hole, and finally backfilling; for collapse roof fall within 20 m of collapse cavity height, the method of open cut on the ground can also be adopted, slope excavation and side slope anchor net spraying support are firstly carried out, and then open arch lining and backfilling in the tunnel are carried out. Both methods require sufficient construction site on the surface to perform. However, for the current collapse, the collapse part is an apple orchard and ginger land with the surface of common people, the collapse can not be completed within the land acquisition range and at least 10-15 days are required for land acquisition, and the collapse treatment cannot be performed immediately. Therefore, in order to complete collapse roof fall treatment as soon as possible and recover normal construction, only a treatment scheme of firstly deslagging from a hole, then carrying out hole top supporting and lining, and finally carrying out backfilling is adopted. The specific processing procedure is as follows:
1) And (5) earth surface seepage control treatment. A rain shed is erected on the ground surface, and drainage ditches are dug manually around the collapsed cavity to prevent surface water from flowing into and permeating into the collapsed cavity in large quantity.
2) And removing soil in the collapsed cavity. The soil body in the collapsed cavity is in a saturated state, the bearing capacity is very low, the total volume is not large, and the volume is about 1500 m 3 On the left and right sides, the collapsed cavity can be exposed by first emptying.
3) And (5) replacing and filling the slag in the hole. Because the collapse slag in the hole is a saturated soil body, the collapse slag cannot be used for building a construction operation platform, and the soil body in the hole must be transported out of the hole completely to replace and fill hole slag materials with higher overall strength.
4) And constructing a collapse treatment operation platform. And (3) constructing a collapse treatment construction platform by adopting the hole slag materials to be changed and filled, wherein the height of the platform is the height of the upper step according to a three-step excavation method.
5) And (5) performing collapsed cavity support treatment. And (3) carrying out concrete spraying construction on the surface of the inner wall of the collapsed cavity on the constructed collapse treatment operation platform, and supporting the inner wall of the collapsed cavity.
6) And (5) carrying out top arch sealing treatment. And (3) carrying out upper step inner sealing treatment on the collapsed cavity by adopting a steel arch frame, a hanging net and sprayed concrete.
7) And carrying out totally-enclosed treatment. And excavating the middle step and the lower step, and carrying out full-circle closed steel arch frame, net hanging and concrete spraying.
8) And (5) constructing inverted arch concrete. And (5) performing inverted arch concrete construction according to design requirements.
9) And (5) constructing the secondary lining concrete. And carrying out full-section secondary lining concrete construction according to design requirements.
10) And (5) backfilling the collapsed cavity of the tunnel top. And (4) performing collapse cavity backfilling work from the earth surface in later land preparation, backfilling natural soil according to design requirements, and naturally settling to be compact.
3. Construction for treating collapse
After negotiation with apple orchard and ginger landlord, temporary treatment is carried out within a certain range of collapse, and meanwhile, a temporary land acquisition procedure is started. The temporary land acquisition is mainly used for construction sites backfilled in the later-stage collapse cavity. Collapse roof fall handling conditions are shown in FIG. 3.
3.1 surface anti-seepage treatment
A rain shed is erected in the range of 10.0 m from the edge of the landslide cavity, a temporary drainage ditch is excavated about 9.0 m away from the edge, the width of the ditch is 50 cm, the depth of the ditch is 30 cm, mortar is applied to the surface, and the drainage ditch extends out of the landslide influence range so as to prevent the landslide cavity from being influenced by seepage of rainwater on the surface.
3.2 removing collapsed slag in collapsed cavity and hole
Using 3.0m 3 The loader digs and loads a 25 t dump truck, and collapsed slag is conveyed to a slag disposal field outside the hole until the collapsed cavity and slag in the hole are completely removed.
3.3 landslide processing platform is built
The stone slag material with better integral strength is transported back to the tunnel face at the lower part of the collapse cavity from the slag disposal site outside the tunnel and adopts 1.2 m 3 Compacting the backhoe caterpillar and the bucket layer by layer, and backfilling to the height of an upper step of the three-step excavation method, namely, the distance between the top surface of the working platform and the top of the tunnel is about 3.7 m.
3.4 spray protection of collapsed cavity inner wall
Standing on a collapse treatment operation platform by adopting an Anhui Jiale HSC-3015C type wet spraying trolley (the maximum spraying height is 15.0 m), extending a manipulator into a collapse cavity, spraying C25 concrete with the thickness of 10-12 cm on the surface of the inner wall of the collapse cavity for three times to ensure that the inner wall of the collapse cavity is stable during collapse treatment and collapse accidents do not occur.
3.5 crown closure construction
1) Erecting a top arch steel arch frame. 3I 22 steel arches at the top arch part are welded outside the tunnel into a whole according to the designed distance of 0.6 m, and I18I steel is adopted for connection. And welding the inner and outer double-layer reinforcing steel bar meshes, wherein the reinforcing steel bar meshes adopt phi 8 mm reinforcing steel bars, and the grid size is 20cm multiplied by 20 cm. In the hole, 1.2m 3 The front arm of the back shovel erects each group of steel arch centering to the top arch position, and the direction and the angle of the steel arch centering are adjusted by the manual work under the protection of surrounding rocks at arch angles at two sides. The arch foot is made of I18I-steel, concrete cushion block, wood wedge and other materials. 6 steel arch frames are erected in two times.
2) And (4) spraying concrete to the top arch. A HSC-3015C type wet-spraying trolley of Anhui Jiale is adopted, and the thickness of top arch sprayed concrete is 30 cm.
3) And (5) constructing a locking guide pipe. 12 small guide pipes with locking feet are arranged on each steel arch frame according to the design requirement of collapse treatment, 6 small guide pipes with the diameter of 42 mm are adopted on each side, and the length of each small guide pipe is 4.0 m. In order to ensure the integral stability of the steel arch, in addition to the small foot-reducing conduits required by design, 2 strengthening conduit feet are additionally arranged between every two steel arches, 1 is arranged on each side, the strengthening conduits are seamless steel pipes with the diameter of 108 mm and the length of 5.0 m, and grouting is carried out in the conduits.
3.6 full-ring sealing construction
And (4) after the top arch sealing construction is finished, excavating the lower step and the inverted arch, adopting I22 steel arch frame for full-circle sealing, hanging a reinforcing mesh and spraying concrete, wherein the specific parameters are the same as the above.
3.7 inverted arch and two-lining concrete construction
The inverted arch concrete construction adopts 36 m long hydraulic inverted arch trestle construction; the full-section secondary lining concrete adopts a two-lining steel mould trolley, and an HBT60A-1406 type concrete pump pumps concrete to be put into a warehouse.
3.8 collapse Cavity backfill
And after the secondary lining concrete construction is finished, backfilling natural soil after the strength reaches the design requirement, naturally settling to be compact, ensuring that the backfilled soil is slightly higher than the elevation of the peripheral earth surface, and filling planting soil with the thickness of not less than 1.2 m on the earth surface. In the backfilling process, soil materials cannot be directly poured vertically, a slope is constructed in the temporary land acquisition, and the slope is pushed by a loader to prevent the soil from pouring to cause cracking of the secondary lining concrete in the hole.
3.9 following excavation construction requirements
1) And controlling the single-cycle footage. After the collapse cavity is processed, the subsequent DK95+ 407.7-DK 95+432.7 sections (25 m) adopt a three-step core soil excavation method according to the grade surrounding rock, and the single-cycle footage is controlled to be 0.6 m.
2) Pipe shed in the construction. Within 25 m of forward excavation, digging a row of pipe sheds in the circumferential 140-degree range of an arch part of every 12.5 m, wherein the circumferential distance is 30 cm, the pipe sheds are made of seamless steel pipes with the diameter of 89 mm, the length of the seamless steel pipes is 15.0 m, and the lap joint length between two rows is 2.5 m.
3) And (3) drilling 45-degree oblique upward exploration holes with the length of 5.0 m at each excavation blasting circulation in the ultra-thin tunnel section of the top arch rock so as to explore the thickness of the rock layer above the arch part and reasonably determine blasting parameters.
4. Comparison of time and economic benefits
The collapse treatment work is completed from collapse roof falling in 21 days earlier in 2021 to collapse roof falling in 28 days in 9 months to concrete spraying, the collapse cavity of the top arch is closed, only 8 days are used, the next subsequent excavation work is started, the speed is high, the collapse roof falling is rare in collapse roof falling treatment of similar projects, and the cost investment of collapse roof falling is minimum. The economic cost is compared with the situation and is shown in the table 1. Treatment times are compared, see table 2.
In table 1, the cost of three different processing methods are compared, wherein the hole processing method is the processing method adopted this time. The shaft treatment method is that the inner wall of a collapsed cavity is treated from top to bottom, anchor net spraying construction is adopted, and the inner wall is sprayed with concrete for the second time by 10 cm; the reinforcing mesh adopts phi 8mm reinforcing steel bars, and the grids are 20cm multiplied by 20 cm; the anchor rod is a mortar anchor rod with the diameter phi of 22mm and the L =4.0m, and the row spacing is 1.5 m. The open cut treatment method is characterized in that slope releasing and expanding excavation is adopted along the periphery of a collapsed cavity, soil bodies around the collapsed cavity are repaired into a 1:1 positive slope, then the slope surface is treated by anchor net spraying and supporting, and concrete is sprayed for 8 cm; the reinforcing mesh adopts phi 8mm reinforcing steel bars, and the grids are 20cm multiplied by 20 cm; the anchor rod is a mortar anchor rod with the diameter phi of 22mm and the L =4.0m, and the row spacing is 2.5 m. Table 2 is a time comparison of the three treatment methods required to treat a collapsed cavity.
TABLE 1 comparison of economic benefits of collapsed Chamber treatment
TABLE 2 collapsed Chamber treatment time comparison
| Serial number | Name of item | Unit of | In-hole treatment method | Wellbore treatment process | Open cut treatment method |
| 1 | Time of land acquisition | Sky | 0 | 10 | 10 |
| 2 | Time of treatment | Sky | 8 | 15 | 18 |
| Total up to | Sky | 8 | 25 | 28 |
As can be seen from table 1, the hole treatment method used this time costs only 64.4% of the shaft treatment method and only 22.2% of the open cut treatment method. The in-hole treatment is 17 days faster than the wellbore treatment and 20 days faster than the open cut treatment.
While one embodiment of the present invention has been described in detail, the description is only a preferred embodiment of the present invention and should not be taken as limiting the scope of the invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.
Claims (6)
1. The collapse roof caving in-hole processing method of the high-speed railway shallow-buried tunnel within the height of a collapsed cavity of 15m is characterized by comprising the following steps of: comprises the following steps of (a) carrying out,
s1, firstly, collapse treatment construction is started in the cave, firstly, slag in the cave is cleaned, soil in the collapse cavity is removed, and the slag of the collapse body is conveyed to the outside of the cave to be discarded to a slag dump until the collapse cavity and the slag in the cave are completely removed and the collapse cavity is exposed;
s2, replacing and filling the slag in the hole, conveying all the collapsed slag in the hole out of the hole, and replacing and filling hole slag with high overall strength;
S3, building a collapse treatment operation platform, namely building the collapse treatment operation platform by adopting the hole slag materials changed and filled in the step S2, wherein the height of the platform is the height of the upper step according to a three-step excavation method;
s4, carrying out collapsed cavity supporting treatment, carrying out concrete spraying construction on the surface of the inner wall of the collapsed cavity on the constructed collapse treatment operation platform, and supporting the inner wall of the collapsed cavity;
s5, top arch sealing treatment, namely, steel arch frames, net hanging and concrete spraying are adopted to carry out upper step inner sealing treatment on the collapse cavity, the step S5 comprises the following steps,
1) erecting top arch steel arch frames, namely welding the steel arch frames at the top arch part into a whole outside a tunnel according to a set of every 3 steel arch frames at a designed interval, welding an inner layer reinforcing mesh and an outer layer reinforcing mesh, erecting each group of steel arch frames at the top arch part, and manually assisting to adjust the direction and the angle of the steel arch frames under the protection of surrounding rocks at arch corners at two sides;
2) ejecting concrete;
3) constructing a foot locking guide pipe, arranging a small foot locking guide pipe with phi 42mm and L =4.0m for each steel arch frame according to the design requirement of collapse treatment, additionally increasing phi 108mm and L =5.0m reinforcing guide pipe shrinking feet between every two steel arch frames, and grouting in the guide pipe;
s6, performing full-closed treatment, excavating middle steps and lower steps, sealing full-circle steel arches, hanging nets and spraying concrete, and in step S6, finishing top arch sealing construction, excavating lower steps and inverted arches, performing full-circle sealing by adopting I22 steel arches, hanging reinforcing steel nets and spraying concrete;
S7, constructing inverted arch concrete;
s8, constructing secondary lining concrete of the full section according to the design requirement;
s9, carrying out cave top collapsed cavity backfilling construction, wherein the collapsed cavity backfilling is carried out in the land expropriation at the later stage of the ground surface, and backfilling according to the design requirement
Natural soil, naturally subsides to be compact;
after the backfilling is finished, the subsequent construction is carried out according to the following steps,
1) controlling the single-cycle footage to be 0.6 m;
2) supporting the pipe shed in construction;
3) in the top arch rock ultrathin tunnel section, 3 obliquely upward 45-degree exploration holes are drilled by hand wind at each excavation blasting circulation, the aperture phi is 42mm, the length is 5.0 m, the thickness of a rock stratum above an arch part is explored, and blasting parameters are determined;
after the collapse cavity is processed, according to
Grade fenceRock, adopting a three-step core soil excavation method;
during construction, excavating a pipe shed forwards within 25 m, digging one row of pipe sheds within 140 degrees in the circumferential direction of an arch part of each 12.5 m, wherein the circumferential distance is 30 cm, the pipe sheds are made of seamless steel pipes with the diameter of 89 mm, the length of each pipe shed is 15.0 m, and the lap joint length between two rows is 2.5 m;
and drilling 3 obliquely upward 45-degree exploration holes by using hand wind at each excavation blasting circulation, wherein the aperture is phi 42mm, and the length is 5.0 m.
2. The method for treating the collapse roof fall tunnel of the high-speed railway shallow-buried tunnel within the height of a collapsed cavity of 15m as claimed in claim 1, wherein: before step S1, earth surface seepage control treatment is carried out, a rain shed is built on the earth surface, and drainage ditches are manually dug around the collapsed cavity to prevent surface water from flowing into and permeating into the collapsed cavity in large quantity.
3. The method for treating the collapse roof fall hole of the high-speed railway shallow-buried tunnel within the collapsed cavity height of 15m as claimed in claim 2, wherein: a rain shed is erected within the range of 10.0 m from the edge of the landslide cavity on the ground surface, a temporary drainage ditch is excavated at the distance of 9.0 m from the edge, the width of the ditch is 50 cm, the depth of the ditch is 30 cm, the mortar is smeared on the surface, and the drainage ditch extends out of the landslide influence range so as to prevent the landslide cavity from being influenced by the seepage of rainwater on the ground surface.
4. The method for treating the collapse roof fall tunnel of the high-speed railway shallow-buried tunnel within the height of a collapsed cavity of 15m as claimed in claim 1, wherein: welding 3I 22 steel arches at the top arch part outside the tunnel at a designed interval of 0.6 m to form a whole, wherein I18I-shaped steel is adopted for connection, and the inner and outer double-layer reinforcing meshes are welded, wherein the reinforcing meshes are 8 mm steel bars, the mesh size is 20cm multiplied by 20cm, and the inner part of the tunnel is 1.2 m 3 Erecting each group of steel arch frames to a top arch part by a front arm of the back shovel, and assisting to adjust the direction and the angle of the steel arch frames under the protection of surrounding rocks at arch angles at two sides by manpower; the arch springing adopts I18I-steel, concrete cushion block and wood wedge cushion, and 6 steel arch frames are erected in two times;
adopting a wet spraying trolley, and spraying concrete on the top arch to reach the thickness of 30 cm;
according to the design requirement of collapse treatment, 12 small guide pipes with locking feet are arranged on each steel arch, 6 guide pipes on each side are made of phi 42 mm seamless steel pipes, the length of each guide pipe is 4.0m, except for the small guide pipes with the reduced feet required by the design, 2 reduced feet of reinforcing guide pipes are additionally arranged between every two steel arches, 1 guide pipe on each side is made of phi 108 mm seamless steel pipes, the length of each guide pipe is 5.0 m, and grouting is conducted in the guide pipes.
5. The method for treating the collapse roof fall tunnel of the high-speed railway shallow-buried tunnel within the height of a collapsed cavity of 15m as claimed in claim 1, wherein: the inverted arch concrete construction adopts 36 m long hydraulic inverted arch trestle construction; the full-section secondary lining concrete adopts a two-lining steel mould trolley, and a concrete pump pumps the concrete into a bin.
6. The method for treating collapse roof fall holes of high-speed shallow-buried tunnels within 15m of the height of collapsed cavities according to any one of claims 1 to 5, wherein: and step S9, backfilling natural soil, naturally settling to be compact, ensuring that the backfilled soil is slightly higher than the elevation of the peripheral earth surface after the backfilling is finished, filling planting soil with the thickness of not less than 1.2 m on the earth surface, wherein in the backfilling process, soil materials cannot be directly poured vertically, a slope is built in a temporary land acquisition, and the slope is pushed in by a loader to prevent the cracking of the secondary lining concrete in the hole caused by the dumping of soil bodies.
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